Stand Biomass and Carbon Stock Assessment of a 42-Year-Old Pinus caribaea Plantation in Jos Wildlife Park, Nigeria

Accurate assessment of forest biomass and carbon stock is crucial for understanding carbon sequestration potential and informing climate mitigation strategies, particularly in species-specific plantations. This study investigated the stand biomass and carbon stock of a 42-year-old Pinus caribaea plantation in Jos Wildlife Park, Plateau State, Nigeria. Systematic line transects and non-destructive sampling techniques were employed to assess wood density (WD), tree volume (V), basal area (BA), aboveground biomass (AGB), belowground biomass (BGB), total biomass (TB), carbon stock, and CO₂ equivalent in the plantation. To compare accuracy, biomass was calculated using both IPCC default values and Sanquetta equations. The mean DBH and tree height ranged from 29.1 cm to 38.3 cm and 9.6 m to 14.8 m, respectively, while the average wood density for the plantation was 490.35 kg/m³. Stand basal area varied from 36.05 m²/ha to 98.41 m²/ha, indicating structural and productivity differences within the plantation. Notably, biomass estimates derived from IPCC default values were 26% higher than those from Sanquetta equations, indicating potential overestimation and the necessity of species-specific allometric models. The total biomass was estimated at 2627.76 t/ha, comprising 2125.72 t/ha (80.9%) AGB and 502.03 t/ha (19.1%) BGB. The total carbon stock was 1313.88 t/ha, corresponding to a CO₂ equivalent of 4817.55 t/ha. These findings demonstrate that the Pinus caribaea plantation serves as a significant carbon reservoir with strong potential for biomass production and climate change mitigation.